Ablation devices utilizing exothermic chemical reactions, system including same, and methods of ablating tissue using same

ABSTRACT

An ablation device includes a handle assembly including a distal end and a probe extending distally from the distal end of the handle assembly. The probe includes a heat-transfer portion and at least one fluid-flow path in fluid communication with the heat-transfer portion. The handle assembly includes at least one fluid reservoir in fluid communication with the at least one fluid-flow path and at least one apparatus configured to cause fluid flow between the at least one fluid reservoir and the heat-transfer portion. The probe is configured to apply thermal energy released by an exothermic chemical reaction that occurs when fluid from the at least one fluid reservoir is caused to flow to the heat-transfer portion.

BACKGROUND

1. Technical Field

The present disclosure relates to ablation devices suitable for use intissue ablation applications and, more particularly, to ablation devicescapable of utilizing exothermic chemical reactions, a system includingthe same, and methods of ablating tissue using the same.

2. Discussion of Related Art

Treatment of certain diseases requires the destruction of malignanttissue growths, e.g., tumors. Tumor treatment depends on a variety offactors such as the tumor's type, size, location, and the overall healthof the patient. Treatment options may include hyperthermia therapy toheat and destroy tumor cells, cryoablation to freeze the tumor to killthe cells, thermochemical ablation therapy to thermally ablate the tumorby using direct injection of ethanol or acetic acid using ultrasound orother guidance and, in some cases, external beam radiation therapy maybe used to destroy tumor cells.

In the treatment of diseases such as cancer, certain types of tumorcells have been found to denature at elevated temperatures that areslightly lower than temperatures normally injurious to healthy cells.Known treatment methods, such as hyperthermia therapy, heat diseasedcells to temperatures above 41° C. while maintaining adjacent healthycells below the temperature at which irreversible cell destructionoccurs. These methods may involve applying electromagnetic radiation toheat, ablate and/or coagulate tissue. Treatment may involve insertingablation probes into tissues where cancerous tumors have beenidentified. Once the probes are positioned, electromagnetic energy ispassed through the probes into surrounding tissue.

Electrosurgical devices utilizing electromagnetic radiation have beendeveloped for a variety of uses and applications. A number of devicesare available that can be used to provide high bursts of energy forshort periods of time to achieve cutting and coagulative effects onvarious tissues. There are a number of different types of apparatus thatcan be used to perform ablation procedures. Typically, microwaveapparatus for use in ablation procedures include a microwave generatorthat functions as an energy source, and a microwave surgical instrument(e.g., microwave ablation probe) having an antenna assembly fordirecting the energy to the target tissue. The microwave generator andsurgical instrument are typically operatively coupled by a cableassembly having a plurality of conductors for transmitting microwaveenergy from the generator to the instrument, and for communicatingcontrol, feedback and identification signals between the instrument andthe generator.

During certain procedures, it can be difficult to assess the extent towhich the microwave energy will radiate into the surrounding tissue,making it difficult to determine the area or volume of surroundingtissue that will be ablated. Tissue ablation devices capable ofdirecting thermal energy to tissue without the use of microwaveradiation may enable more precise ablation treatments, which may lead toshorter patient recovery times, fewer complications from undesiredtissue damage, and improved patient outcomes.

Tissue ablation devices capable of directing thermal energy to heat,ablate and/or coagulate tissue without the use of electromagneticradiation may enhance device portability and location independence, andmay help to facilitate improved patient accessibility to hyperthermictreatments.

SUMMARY

The present disclosure relates to an ablation device including a handleassembly including a distal end and a probe extending distally from thedistal end of the handle assembly. The probe includes a heat-transferportion and at least one fluid-flow path in fluid communication with theheat-transfer portion. The handle assembly includes at least one fluidreservoir in fluid communication with the at least one fluid-flow pathand at least one apparatus configured to cause fluid flow between the atleast one fluid reservoir and the heat-transfer portion. The probe isconfigured to apply thermal energy released by an exothermic chemicalreaction that occurs when fluid from the at least one fluid reservoir iscaused to flow to the heat-transfer portion.

The present disclosure also relates to a system for ablating tissueincluding an ablation device capable of utilizing an exothermic chemicalreaction. The ablation device includes a handle assembly including acartridge unit and a probe extending distally from a distal end of thehandle assembly. The cartridge unit includes a first chamber containinga first fluid and a second chamber containing a second fluid. The probeincludes a mixing junction and first and second fluid-flow paths influid communication with the mixing junction. The first fluid-flow pathis in fluid communication with the first chamber, and the secondfluid-flow path is in fluid communication with the second chamber.

The present disclosure also relates to a method of delivering thermalenergy to tissue including the initial step of providing an ablationdevice including a handle assembly and a probe operably coupled to thehandle assembly. The probe includes a heat-transfer portion and at leastone fluid-flow path defined therein and disposed in fluid communicationwith the heat-transfer portion. The handle assembly includes at leastone fluid reservoir in fluid communication with the at least onefluid-flow path. The method also includes the steps of positioning theprobe in tissue, causing an exothermic chemical reaction within the atleast one fluid flow path of the probe, and delivering thermal energyreleased by the exothermic chemical reaction through the heat-transferportion of the probe to tissue.

The present disclosure also relates to a method of delivering thermalenergy to tissue including the initial step of providing an ablationdevice including a handle assembly and a probe extending distally from adistal end of the handle assembly. The handle assembly includes acartridge housing a first chamber defined therein and configured tocontain an acid and a second chamber defined therein and configured tocontain a base. The probe includes a mixing junction and first andsecond fluid-flow paths in fluid communication with the mixing junction.The first fluid-flow path is in fluid communication with the firstchamber, and the second fluid-flow path is in fluid communication withthe second chamber. The method also includes the steps of positioningthe probe in tissue, moving one or more moveable members operablycoupled to the cartridge to cause fluid flow of the acid and the base tothe mixing junction to cause an exothermic chemical reaction, anddelivering thermal energy released by the exothermic chemical reactionthrough at least a portion of the probe to tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

Objects and features of the presently disclosed ablation devicesutilizing exothermic chemical reactions, system including the same, andmethods of ablating tissue using the same will become apparent to thoseof ordinary skill in the art when descriptions of various embodimentsthereof are read with reference to the accompanying drawings, of which:

FIG. 1 is a block diagram of a heat-generating system for carrying outan exothermic chemical reaction to produce thermal energy according toan embodiment of the present disclosure;

FIG. 2 is a schematic diagram of an embodiment of an ablation devicecapable of utilizing an exothermic chemical reaction for applyingablative thermal energy to tissue in accordance with the presentdisclosure;

FIG. 3 is a schematic diagram of an ablation system including anembodiment of an ablation device capable of utilizing an exothermicchemical reaction for applying ablative thermal energy to tissue inaccordance with an embodiment of the present disclosure;

FIG. 4A is a cross-sectional view of a proximal portion of the probe ofthe ablation device of FIG. 3 taken along section lines 4A-4A accordingto an embodiment of the present disclosure;

FIGS. 4B through 4I are cross-sectional views of a fluid-mixing portionof the probe of the ablation device of FIG. 3 taken along section lines4B-4B through 4I-4I, respectively, according to an embodiment of thepresent disclosure;

FIGS. 4J and 4K are cross-sectional views of a distal portion of theprobe of the ablation device of FIG. 3 taken along section lines 4J-4Jand 4K-4K, respectively, according to an embodiment of the presentdisclosure;

FIG. 5 is a perspective view of another embodiment of an ablation devicecapable of utilizing an exothermic chemical reaction for applyingablative thermal energy to tissue in accordance with the presentdisclosure;

FIG. 6 is partial, cross-sectional side perspective view of theindicated area of detail of FIG. 5 according to an embodiment of thepresent disclosure;

FIG. 7A is a cross-sectional view of a proximal portion of the probe ofthe ablation device of FIG. 5 including a cooling jacket disposedthereabout taken along section lines 7A-7A according to an embodiment ofthe present disclosure;

FIGS. 7B through 7H are cross-sectional views of a fluid-mixing portionof the probe of the ablation device of FIG. 5 including a cooling jacketdisposed thereabout taken along section lines 7B-7B through 7H-7H,respectively, according to an embodiment of the present disclosure;

FIGS. 7I through 7K are cross-sectional views of a heat-transfer portionof the probe of the ablation device of FIG. 5 taken along section lines7I-7I through 7K-7K, respectively, according to an embodiment of thepresent disclosure;

FIG. 8 is a partial, schematic diagram of an apparatus capable ofgenerating fluid flow by controlling the position of one or more pistonswithin one or more fluid reservoirs of a cartridge unit according to anembodiment of the present disclosure;

FIG. 9 is a flowchart illustrating a method of ablating tissue accordingto an embodiment of the present disclosure; and

FIG. 10 is a flowchart illustrating a method of ablating tissueaccording to another embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, embodiments of the presently disclosed ablation devicesutilizing exothermic chemical reactions, system including the same, andmethods of ablating tissue using the same are described with referenceto the accompanying drawings. Like reference numerals may refer tosimilar or identical elements throughout the description of the figures.As shown in the drawings and as used in this description, and as istraditional when referring to relative positioning on an object, theterm “proximal” refers to that portion of the apparatus, or componentthereof, that is closer to the user and the term “distal” refers to thatportion of apparatus, or component thereof, that is farther from theuser.

This description may use the phrases “in an embodiment,” “inembodiments,” “in some embodiments,” or “in other embodiments,” whichmay each refer to one or more of the same or different embodiments inaccordance with the present disclosure. For the purposes of thisdescription, a phrase in the form “A/B” means A or B. For the purposesof the description, a phrase in the form “A and/or B” means “(A), (B),or (A and B)”. For the purposes of this description, a phrase in theform “at least one of A, B, or C” means “(A), (B), (C), (A and B), (Aand C), (B and C), or (A, B and C)”.

As it is used in this description, “fluid” generally refers to a liquid,a gas or both. As it is used in this description, “pressure” generallyrefers to positive pressure, negative pressure or both. As it is used inthis description, “exothermic chemical reaction”, or “exothermicreaction” for short, generally refers to a chemical reaction thatreleases energy in the form of heat.

As it is used in this description, “acid” generally refers to anychemical compound that, when dissolved in water, gives a solution with ahydrogen ion activity greater than in pure water, e.g., a pH less than7.0 (at 25° C.) in its standard state. The strength of an acid or a baseis determined by its ability to ionize in water. The percent ionizationof an acid or base may be defined as the percent of the total moleculesof the acid or base that react with water to form hydronium or hydroxylions. Acids that ionize 95% or better in water are usually referred toas strong acids. An acid that ionizes less than 95% in water may bereferred to as a weak acid. There is no clear demarcation line betweenstrong and weak acids and between strong and weak bases. Rather there isa continuum in the strengths of each.

As it is used in this description, “actuator” generally refers to anydevice that converts one form of applied power to a useable form ofpower that provides motion of a moveable member. Actuators may begenerally classified into hydraulic, pneumatic, and electro-mechanicalactuators. Electro-mechanical actuators generally include an electricmotor and one or more drive train components to transfer and/or convertpower provided by the electric motor to a moveable member. As it is usedin this description, “switch” or “switches” includes any electricalactuators, mechanical actuators, electro-mechanical actuators (rotatableactuators, pivotable actuators, toggle-like actuators, buttons, etc.) oroptical actuators.

As it is used in this description, “transmission line” generally refersto any transmission medium that can be used for the propagation ofsignals from one point to another. As it is used in this description,“length” may refer to electrical length or physical length. In general,electrical length is an expression of the length of a transmissionmedium in terms of the wavelength of a signal propagating within themedium. Electrical length is normally expressed in terms of wavelength,radians or degrees. For example, electrical length may be expressed as amultiple or sub-multiple of the wavelength of an electromagnetic wave orelectrical signal propagating within a transmission medium. Thewavelength may be expressed in radians or in artificial units of angularmeasure, such as degrees. The electric length of a transmission mediummay be expressed as its physical length multiplied by the ratio of (a)the propagation time of an electrical or electromagnetic signal throughthe medium to (b) the propagation time of an electromagnetic wave infree space over a distance equal to the physical length of the medium.The electrical length is in general different from the physical length.By the addition of an appropriate reactive element (capacitive orinductive), the electrical length may be made significantly shorter orlonger than the physical length.

Various embodiments of the present disclosure provide ablation devicescapable of utilizing an exothermic chemical reaction to produce heat fortreating tissue and methods of delivering ablative thermal energy totissue.

Various embodiments of the presently disclosed ablation devices capableof utilizing an exothermic reaction and electrosurgical systemsincluding the same are suitable for ablation and for use topre-coagulate tissue for ablation-assisted surgical resection. Althoughvarious methods described hereinbelow are targeted toward ablation andthe complete destruction of target tissue, it is to be understood thatmethods for directing thermal energy may be used with other therapies inwhich the target tissue is partially destroyed or damaged, such as, forexample, to prevent the conduction of electrical impulses within hearttissue.

It is envisioned and within the scope of the present disclosure that anycombination of battery cells, a battery pack, fuel cell and/orhigh-energy capacitor may be used to provide power to the ablationdevice (e.g., 101, 102 and 103 shown in FIGS. 2, 3 and 5, respectively).For example, capacitors may be used in conjunction with a battery pack.In such case, the capacitors may discharge a burst of power to provideenergy more quickly than batteries are capable of providing, asbatteries are typically slow-drain devices from which current cannot bequickly drawn. It is envisioned that batteries may be connected to thecapacitors to charge the capacitors.

A battery pack may include at least one disposable battery. In suchcase, the disposable battery may be between about 9 volts and about 30volts, and may be useful as a primary power source for a processor unit(e.g., 226 shown in FIG. 2). In some embodiments, a transmission line(e.g., 15 shown in FIG. 3) is provided to connect the ablation device(e.g., 102 shown in FIG. 3) to a line source voltage or external powersource (e.g., 48 shown in FIG. 3), in which case a battery pack may beused as a backup power source.

FIG. 1 shows a schematic of a heat-generating system 10 for use incarrying out an exothermic reaction to produce thermal energy (showngenerally as “H” in FIG. 1). Heat-generating system 10 generallyincludes a processor unit 26, a user interface 70 operably associatedwith the processor unit 26, and an exothermic reaction unit 11configured to selectively carry out an exothermic chemical reaction inwhich thermal energy is released.

Exothermic reaction unit 11 includes one or more controllable actuators(e.g., 31, 32 and 33) operably associated with one or more fluidreservoirs (e.g., 41, 42 and 43) and/or one or more fluid flow paths(e.g., 131, 132 and 133), and may be operably associated with theprocessor unit 26. The actuators may be of any suitable type. Examplesof types of actuators that may be suitable include hydraulic actuators,pneumatic actuators, and electro-mechanical actuators. Processor unit 26is communicatively associated with the one or more actuators and adaptedto generate an electric signal for controlling an operation of the oneor more actuators, e.g., to supply force and motion to position one ormore moveable members (e.g., 380 shown in FIG. 3) operably associatedtherewith. Logic associated with one or more actuators may control anoperation of the actuator in response to a user-initiated action. Insome embodiments, the user interface 70 includes a user-operable switch(e.g., 21 shown in FIG. 2) that is electrically coupled to the processorunit 26. A user-operable switch may additionally, or alternatively, bemechanically coupled to one or more actuators for selectively generatinga fluid flow when mechanical force is applied thereto.

In some embodiments, the user interface 70 may include a fluid-flowmonitoring system adapted to monitor and/or regulate the pressure and/orflow rate of fluid and capable of generating a signal indicative of anabnormal fluid-flow condition. User interface 70 may additionally, oralternatively, include audio and/or visual indicator devices. Userfeedback may be included in the form of pulsed patterns of light,acoustic feedback (e.g., buzzers, bells or beeps that may be sounded atselected time intervals), verbal feedback, and/or haptic vibratoryfeedback (such as an asynchronous motor or solenoids), for example.

Processor unit 26 is operably associated with a power source 16, e.g., abattery pack. Processor unit 26 may include any type of computingdevice, computational circuit, or any type of processor or processingcircuit capable of executing a series of instructions that are stored ina memory (not shown) of the processor unit 26. The series ofinstructions may be transmitted via propagated signals for execution bythe processor unit 26 for performing the functions described herein andto achieve a technical effect in accordance with the present disclosure.It is envisioned and within the scope of the present disclosure that theheat-generating system 10 may include a temperature sensor, e.g., athermocouple, which may be monitored by the processor unit 26.

Heat-generating system 10 according to an embodiment of the presentdisclosure includes a first actuator 31 operably associated with a firstfluid flow path 131, a second actuator 32 operably associated with asecond fluid flow path 132, and a third actuator 33 operably associatedwith a third fluid flow path 133. First fluid flow path 131 is in fluidcommunication with a first reservoir 41. First reservoir 41 is capableof containing a quantity of a first fluid “F1”, and may be capable ofholding the first fluid “F1” under pressure. Second fluid flow path 132is in fluid communication with a second reservoir 42. Second reservoir42 is capable of containing a quantity of a second fluid “F2”, and maybe capable of holding the second fluid “F2” under pressure. Third fluidflow path 133 is in fluid communication with a third reservoir 43, whichis capable of containing a quantity of a third fluid “F3”.

First fluid “F1” and the second fluid “F2” may include any reagent orreactant suitable for use in an exothermic reaction to produce thermalenergy for treating tissue, e.g., ablative thermal energy. The portionof the first fluid “F1” that serves as a reactant (e.g., reactable withthe second fluid “F2” to produce an exothermic reaction) may be referredto herein as a “first reactant portion”, and the portion of the secondfluid “F2” that serves as a reactant (e.g., reactable with the firstfluid “F1” to produce an exothermic reaction) may be referred to hereinas a “second reactant portion”.

In some embodiments, the first fluid “F1” may be an acid and the secondfluid “F2” may be a base. It will be appreciated that the first fluid“F1” may be a base and the second fluid “F2” may be an acid. Third fluid“F3” may include products of a reaction, e.g., an acid-base reaction,between the first fluid “F1” and the second fluid “F2”. In someembodiments, the third fluid “F3” may be a coolant fluid, e.g., water orsaline.

In some embodiments, the first fluid “F1” includes a strong acid, andthe second fluid “F2” may include a weak base. Substances that ionize95% or better in water are usually referred to as strong acids. Examplesof strong acids include hydrochloric acid (HCl), hydrobromic acid (HBr),hydroiodic acid (HI), sulfuric acid (H₂SO₄), nitric acid (HNO₃), chloricacid (HClO₃) and perchioric acid (HClO₄). Examples of weak bases includealanine (C₅H₅NH₂), ammonia (NH₃), methylamine (CH₃NH₂) and pyridine(C₅H₅N). In some embodiments, the second fluid “F2” includes a strongbase, and the first fluid “F1” may include a weak acid. Examples ofstrong bases include potassium hydroxide (KOH), barium hydroxide(Ba(OH)₂), caesium hydroxide (CsOH), sodium hydroxide (NaOH), strontiumhydroxide (Sr(OH)₂), calcium hydroxide (Ca(OH)₂), lithium hydroxide(LiOH), rubidium hydroxide (RbOH) and magnesium hydroxide (Mg(OH)₂).Examples of weak acids include acetic acid (CH₃COOH) and oxalic acid(H₂C₂O₄).

In some embodiments, the first fluid “F1” includes HCl and the secondfluid “F2” includes any suitable metal oxides reactable with HCl toproduce an exothermic reaction. In one embodiment, the first fluid “F1”includes hydrochloric acid (HCl), the second fluid “F2” includes sodiumhydroxide (NaOH), and the third fluid “F3” includes water (H₂O) and salt(NaCl) produced by the HCl+NaOH reaction. It is envisioned and withinthe scope of the present disclosure that other chemical compounds andsubstances reactable to produce an exothermic reaction may be utilizedby the presently disclosed heat-generating system 10. For example, othersubstances reactable to produce an exothermic reaction may includeNa(s)+0.5Cl₂(s)→NaCl (s)+heat in an amount of 411 kilojoules (kJ) permole of NaCl produced.

As illustrated in FIG. 1, the flow of the first fluid “F1” through thefirst fluid flow path 131 and the flow of the second fluid “F2” throughthe second fluid flow path 132 merge at a mixing junction 60. Uponmixing of the first and second fluids “F1” and “F2”, a chemical reactionoccurs that releases thermal energy (shown generally as “H” in FIG. 1),e.g., sufficient to cause localized tissue heating around a portion 133a of the third fluid flow path 133. In some embodiments, a quantity of afirst reactant portion may be mixed with a quantity of a second reactantportion to control the reaction rate and/or provide atemperature-controlled ablation procedure, e.g., by controlling therange of temperature between minimum and maximum temperature and/or therate of change of temperature. In some embodiments, the first reactantportion and/or the second reactant portion may be limited to a quantitythat produces only the desired amount of heat. In some embodiments, thequantity of the first reactant portion is exceeded by the quantity ofthe second reactant portion. For example, in the case of Na+0.5Cl₂→NaCl,if the quantity of sodium is doubled while the quantity of chlorine isnot increased, such that 2Na+0.5Cl₂→NaCl+Na, then the quantity ofchlorine limits the reaction.

FIG. 2 shows an ablation device 101 configured to utilize an exothermicchemical reaction for applying ablative thermal energy to tissueaccording to an embodiment of the present disclosure that includes anapplicator or probe 100. Ablation device 101 generally includes a handleassembly 200 including a grip portion 275 and a handle body 273configured to support the probe 100 at a distal end 3 thereof. Handleassembly 200, according to various embodiments, may be fabricated frommetals, plastics, ceramics, composites, e.g., plastic-metal orceramic-metal composites, or other materials. The shape and size of thehandle assembly 200 and the probe 100 may be varied from theconfiguration depicted in FIG. 2.

Probe 100 generally includes one or more fluid flow paths (e.g., 52, 55and 58 shown in FIG. 2) configured to allow mixing and/or delivery offluid to a heat-transfer portion 12 of the probe 100. Probe 100 may beconfigured to be detachably mountable to the distal end 3 of handle body273, and may be disposable. In some embodiments, the ablation device 101may be configured to allow for replacement of the cartridge unit 40and/or the probe 100.

Probe 100, or portion thereof, includes a thermally-conductive material,such as, for example, copper, stainless steel, titanium, titanium alloyssuch as nickel-titanium and titanium-aluminum-vanadium alloys, aluminum,aluminum alloys, tungsten carbide alloys or combinations thereof. Insome embodiments, the probe 100, or portion thereof, may be providedwith an outer jacket (not shown) disposed at least partially thereabout.The outer jacket may be formed of any suitable material, such as, forexample, polymeric or ceramic materials. The outer jacket may be appliedby any suitable method, such as, for example, heat shrinking,over-molding, coating, spraying dipping, powder coating, baking and/orfilm deposition.

Heat-transfer portion 12 of the probe 100 may be formed of a highthermally conductive material, e.g., aluminum. Heat-transfer portion 12may terminate in a sharp tip 23 to allow for insertion into tissue withminimal resistance. Heat-transfer portion 12 may include other shapes,such as, for example, a tip 23 that is rounded, flat, square, hexagonal,or cylindroconical.

During an ablation procedure, the probe 100 is inserted into or placedadjacent to tissue and thermal energy is supplied thereto. Probe 100 maybe placed percutaneously or surgically, e.g., using conventionalsurgical techniques by surgical staff. A clinician may pre-determine thelength of time that thermal energy is to be applied. Applicationduration may depend on a variety of factors such as applicator design,number of applicators used simultaneously, tumor size and location, andwhether the tumor was a secondary or primary cancer. The duration ofthermal energy application using the probe 100 may depend on theprogress of the heat distribution within the tissue area that is to bedestroyed and/or the surrounding tissue. Through limitation of thequantity of a reactant, the amount of thermal energy generated may becontrolled. The rate of flow of the reactant and/or its concentrationmay be adjustable to ensure that only a predetermined amount of energyis available during one application. Thermal probes may also be used tomonitor and measure temperature of the reaction product. In someembodiments, a feedback loop may be used to allow adjustment of the rateof flow and/or concentration of the reactant(s) based on the measuredtemperature of the reaction product.

Handle body 273 may include a retaining mechanism 14 configured todetachably hold the probe 100. In some embodiments, the retainingmechanism 14 includes a retainer member that is movable between at leastan engagement position and a released position. In some embodiments, theablation device 101 may include a user-operable switch mechanicallycoupled to the handle body 273, e.g., a push button, operable to movethe retaining mechanism 14 from an engagement position, in which theretainer member is engaged with a connector member of the probe 100, toa released position, in which the retainer member is disengaged from theconnector member of the probe 100.

Ablation device 101 according to some embodiments includes aself-contained, power unit 216 and a processor unit 226 that iselectrically coupled to the power unit 216. Ablation device 101 may beconfigured to allow for user replacement of the power unit 216. Powerunit 216 may be disposed within the handle assembly 200, e.g., withinthe grip portion 275 and/for the handle body 273. For example, thehandle assembly 200 may be equipped with a battery chamber assessablethrough a manageable lid. This may include a screw fastener, snap, orother suitable fasting closure means. Power unit 216 may include one ormore batteries, which may be a rechargeable type such as a nickelcadmium battery. Ablation device 101 may additionally, or alternatively,be operably coupled to a line source voltage or external power source(e.g., 48 shown in FIG. 3). Processor unit 226 is similar to theprocessor unit 26 of FIG. 1 and further description thereof is omittedin the interests of brevity.

Ablation device 101 includes a user-operable trigger mechanism or switch21 that is operably associated with the processor unit 226. Processorunit 226 may control an operation of an actuator unit 30 in response tothe activation of the switch 21. In an embodiment, the user-operableswitch 21 includes a trigger 211 located within a trigger guard 212. Theshape and size of the trigger 211 and the trigger guard 212 may bevaried from the configuration depicted in FIG. 2. Switch 21 may utilizeany suitable switch configuration. Examples of switch configurationsthat may be suitable for use with the ablation device 101 include, butare not limited to, pushbutton, toggle, rocker (e.g., 521 shown in FIG.5), tactile, snap, rotary, slide, and thumbwheel. As an alternative to,or in addition to, the switch 21, the ablation device 101 may includevoice input technology, which may include hardware and/or softwareincorporated in the processor unit 226, or a separate digital moduleconnected to the processor unit 226. The voice input technology mayinclude voice recognition, voice activation, voice rectification, and/orembedded speech.

Ablation device 101 includes a first fluid-flow path 50 and a secondfluid-flow path 53, and may include a third fluid-flow path 56. In someembodiments, a portion 51 of the first fluid-flow path 50, a portion 54of the second fluid-flow path 53, and a portion 57 of the thirdfluid-flow path 56 are disposed within the handle assembly 200, and aportion 52 of the first fluid-flow path 50, a portion 55 of the secondfluid-flow path 53, and a portion 58 of the third fluid-flow path 56 aredisposed within the probe 100. Ablation device 101 may be provided withone or more connectors configured to releasably couple the portions 51,52 of the first fluid-flow path 50, the portions 54, 55 of the secondfluid-flow path 53, and/or the portions 57, 58 of the third fluid-flowpath 56.

Ablation device 101 includes an actuator unit 30 that is operablyassociated with a cartridge unit 40. Actuator unit 30 may additionallybe operably associated with the power unit 216 and/or other powersource. Actuator unit 30 generally includes one or more actuators. Insome embodiments, the processor unit 226 is communicatively associatedwith the one or more actuators and adapted to generate an electricsignal for controlling an operation of the one or more actuators. In anembodiment, the actuator unit 30 includes a first actuator 231 operablyassociated with a first reservoir 241, a second actuator 232 operablyassociated with a second reservoir 242, and a third actuator 233operably associated with a third reservoir 243. First, second and thirdactuators 231, 232 and 233 and the first, second and third reservoirs241, 242 and 243 are similar to the first, second and third actuators31, 32 and 33 and the first, second and third reservoirs 41, 42 and 43,respectively, shown in FIG. 1, and further description thereof isomitted in the interests of brevity.

FIG. 3 shows an ablation system 20 including an embodiment of anablation device 102 capable of utilizing an exothermic chemical reactionfor applying ablative thermal energy to tissue in accordance with thepresent disclosure. Ablation device 102 generally includes a handleassembly 300 including a grip portion 375 and a handle body 373configured to support an applicator or probe 110 at a distal end 7thereof. It will be understood, however, that other probe embodiments(e.g., 103 shown in FIG. 5) may be used.

In some embodiments, the ablation device 102 is electrically connectedvia a transmission line 15 to a connector 17, which may further operablyconnect the ablation device 102 to a line source voltage or externalpower source 48. Transmission line 15 may additionally, oralternatively, provide a conduit (not shown) configured to providecoolant from a coolant source 18 to the probe 110.

During a procedure, e.g., an ablation procedure, using theelectrosurgical system 20, the probe 110 is inserted into or placedadjacent to tissue and thermal energy is supplied thereto. Ultrasound orcomputed tomography (CT) guidance may be used to accurately guide theprobe 110 into the area of tissue to be treated. A plurality of probes110 may be placed in variously-arranged configurations to substantiallysimultaneously ablate a target tissue region, making faster procedurespossible. Multiple probes 110 may be used to synergistically create alarge ablation or to ablate separate sites simultaneously. Probe 110generally includes one or more fluid flow paths configured to allowmixing and/or delivery of fluid to a heat-transfer portion 365 of theprobe 110.

Ablation device 102 includes a processor unit 326, which may be operablyassociated with the power unit 316 and/or the external power source 48.Processor unit 326 is similar to the processor unit 26 of FIG. 1 andfurther description thereof is omitted in the interests of brevity.

Ablation device 102 includes an actuator unit 330. Actuator unit 330 mayinclude any suitable number of actuators. Actuator unit 330 is operablyassociated with a cartridge unit 340. Probe 100 generally includes aplurality of fluid-flow paths in fluid communication with the cartridgeunit 340 via a plurality of fluid-flow paths (e.g., 350, 353, 356 and359) disposed within the handle assembly 300. Actuator unit 330according to an embodiment of the present disclosure includes a firstactuator 331 operably associated with a first fluid flow path 350, asecond actuator 332 operably associated with a second fluid flow path353, a third actuator 333 operably associated with a third fluid flowpath 356, and a fourth actuator 334 operably associated with a fourthfluid flow path 359.

Cartridge unit 340 includes a first reservoir 341, a second reservoir342 and a third reservoir 343, and may include a fourth reservoir 344.In some embodiments, the cartridge unit 340 is similar to the cartridgeunit 40 of FIG. 1, except that the cartridge unit 340 includes a fourthreservoir 344 that is configured to contain a coolant fluid, e.g.,water, in fluid communication with a fourth fluid-flow path 359.

As shown in FIG. 4A, a proximal portion of the probe 110 may be providedwith a fluid-flow path for conveying an acid, A, flow therein; afluid-flow path for conveying a base, B, flow therein; a plurality offluid-flow paths for conveying water, W, flow therein; and a fluid-flowpath for conveying flow of a product, P, e.g., formed during anexothermic chemical reaction. FIGS. 4B through 4I show an embodiment offluid-flow paths forming a fluid-mixing portion 360 (shown in FIG. 3) ofthe probe 110 in accordance with the present disclosure. An embodimentof a fluid-flow path for conveying flow of the product, P, within adistal portion of the probe 110 is shown in FIGS, 4J and 4K. The shape,size and relative spacing of the fluid-flow paths of the probe 110 maybe varied from the configurations depicted in FIGS. 4A through 4K.

In other embodiments, the probe 110, or portion thereof, may be providedwith an outer coolant chamber (e.g., 715 and 716 shown in FIG. 7A),Additionally, the probe 110 may include coolant inflow and outflow ports(not shown) to facilitate the flow of coolant into, and out of, thecoolant chamber. Examples of coolant chamber and coolant inflow andoutflow port embodiments are disclosed in commonly assigned U.S. patentapplication Ser. No. 12/401,268 filed on Mar. 10, 2009, entitled “COOLEDDIELECTRICALLY BUFFERED MICROWAVE DIPOLE ANTENNA”, and U.S. Pat. No.7,311,703, entitled “DEVICES AND METHODS FOR COOLING MICROWAVEANTENNAS”.

FIG. 5 shows an ablation device 103 capable of utilizing an exothermicchemical reaction for applying ablative thermal energy to tissueaccording to an embodiment of the present disclosure. Ablation device103 generally includes a handle assembly 500 including a grip portion575 and a handle body 573 configured to support an applicator or probe1000 at a distal end thereof. Handle assembly 500 includes a controller526, a switch 521, and an indicator unit 520 including one or morelight-emitting elements (e.g., 221 and 222). The shape and size of thehandle assembly 500 and the probe 1000 may be varied from theconfiguration depicted in FIG. 5.

Switch 521 may be any suitable switch that generally fulfills thepurpose of switching electrical circuits on and off or switching overfrom one electrical circuit to another. In the embodiment illustrated inFIG. 5, the switch 521 is a rocker-type switch that generally includestwo wing portions projecting from opposite sides of a rotational axisfor alternatingly engaging depressible operators of the switch 521. Theshape, size and location of the switch 521 may be varied from theconfiguration depicted in FIG. 5

In an embodiment, the indicator unit 520 may include a first LED 221 anda second LED 222. In some embodiments, a change in color of the firstLED 221 and/or the second LED 222 may be used to indicate auser-initiated action and/or to signal temperature-related information.Indicator unit 520 may be used to signal the occurrence of an abnormalfluid-flow condition, or other condition, e.g., low-battery condition.

Ablation device 103 includes an actuator unit 530 that is operablyassociated with a cartridge unit 540. Cartridge unit 540 includes one ormore reservoirs configured to contain fluids therein, e.g., three orfour reservoirs, and may be formed of any suitable material. Cartridgeunit 540 may be adapted to be removeably coupleable to an actuator 540.The reservoirs may have any suitable size, shape and capacity or storagevolume. In an embodiment, the cartridge unit 540 includes a firstreservoir configured to contain a first fluid, e.g., an acid, a secondreservoir configured to contain a second fluid, e.g., a base, a thirdreservoir configured to contain a third fluid, e.g., water or saline,and a fourth reservoir configured to receive a flow of a fourth fluid,e.g., water and/or a product of an exothermic chemical reaction. Thecapacity of the fourth reservoir may be sufficient to allow the fourthreservoir to receive and contain the first, second and/or third fluidtherein. In various embodiments, the ablation device 103 may beconfigured to allow for replacement of the cartridge unit 540 and/or theprobe 1000.

Probe 1000 generally includes a plurality of fluid-flow paths in fluidcommunication with the cartridge unit 540. As shown in FIG. 6, aproximal portion of the probe 1000 may be provided with a fluid-flowpath for conveying an acid, A, flow therein, a fluid-flow path forconveying a base, B, flow therein, a fluid-flow path for conveying flowof a product, P, e.g., formed during an exothermic chemical reaction,and an outer coolant chamber including first and second portions 626 and628 for conveying water, flow therein.

FIG. 8 shows an apparatus capable of generating fluid flow bycontrolling the position of one or more pistons or plungers (e.g., “P1”,“P2” and “P3”) within one or more fluid reservoirs (e.g., 541, 542 and543) of a cartridge unit 540 according to an embodiment of the presentdisclosure. Cartridge unit 540 is operably associated with an actuatorunit 530. Actuator unit 530 is operably associated with a processor unit26, and may include any number of actuators of any suitable type, e.g.,electromechanical actuators. Actuator unit 530 may include steppermotors and various servo motors, coupled with gears. In an embodiment, afirst plunger “P1” is mechanically coupled to a first actuator 531through a mechanical coupling, a second plunger “P2” is mechanicallycoupled to a second actuator 532 through a mechanical coupling, and athird plunger “P3” is mechanically coupled to a third actuator 533through a mechanical coupling.

Under the control of the processor unit 26, the first actuator 531causes the first plunger “P1” to expel a volume of a first fluid “F1”contained within the first reservoir 541, and the second actuator 532causes the second plunger “P2” to expel a volume of a second fluid “F2”contained within the second reservoir 542. In an alternative embodiment,one actuator may be mechanically coupled to both the first and secondplungers “P1” and “P2”, instead of the first and second actuators 531and 532 shown in FIG. 8. In some embodiments, under the control of theprocessor unit 26, the third actuator 533 causes the third plunger “P3”to expel a volume of a third fluid “F3”, e.g., water, and/or to collecta volume of a product formed during an exothermic chemical reaction.

Hereinafter, methods of delivering thermal energy to tissue aredescribed with reference to FIGS. 9 and 10. It is to be understood thatthe steps of the methods provided herein may be performed in combinationand in a different order than presented herein without departing fromthe scope of the disclosure.

FIG. 9 is a flowchart illustrating a method of delivering thermal energyto tissue according to an embodiment of the present disclosure. In step910, an ablation device (e.g., 101 shown in FIG. 2) is provided. Theablation device (e.g., 101 shown in FIG. 2) includes a handle assembly(e.g., 200 shown in FIG. 2) and a probe (e.g., 100 shown in FIG. 2)operably coupled to the handle assembly. The probe (e.g., 101 shown inFIG. 2) includes a heat-transfer portion (e.g., 12 shown in FIG. 2) andone or more fluid-flow paths (e.g., 50, 53 and 56 shown in FIG. 2) influid communication with the heat-transfer portion. The handle assembly(e.g., 200 shown in FIG. 2) includes one or more fluid reservoirs (e.g.,241, 242 and 243 shown in FIG. 2) in fluid communication with the one ormore fluid-flow paths (e.g., 50, 53 and 56 shown in FIG. 2).

In step 920, the probe (e.g., 100 shown in FIG. 2) is positioned intissue. The probe may be inserted directly into tissue, inserted througha lumen, e.g., a vein, needle or catheter, placed into the body duringsurgery by a clinician, or positioned in the body by other suitablemethods.

In step 930, an exothermic chemical reaction is caused within the one ormore fluid-flow paths (e.g., 52, 55 and 58 shown in FIG. 2) of the probe(e.g., 100 shown in FIG. 2). The step 930 of causing an exothermicchemical reaction within the one or more fluid-flow paths (e.g., 350,353, 356 and 359 shown in FIG. 3) of the probe (e.g., 110 shown in FIG.3) may include causing fluid flow of an acid and a base to a mixingjunction (e.g., 360 shown in FIG. 3) of the probe (e.g., 110 shown inFIG. 3). In some embodiments, the acid may be selected from the groupconsisting of hydrochloric acid (HCl), hydrobromic acid (HBr),hydroiodic acid (HI), sulfuric acid (H₂SO₄), nitric acid (HNO₃), chloricacid (HClO₃) and/or perchloric acid (HClO₄). In some embodiments, thebase may be selected from the group consisting of potassium hydroxide(KOH), barium hydroxide (Ba(OH)₂), caesium hydroxide (CsOH), sodiumhydroxide (NaOH), strontium hydroxide (Sr(OH)₂), calcium hydroxide(Ca(OH)₂), lithium hydroxide (LiOH), rubidium hydroxide (RbOH) and/ormagnesium hydroxide (Mg(OH)₂).

In step 940, thermal energy released by the exothermic chemical reactionis delivered through the heat-transfer portion (e.g., 12 shown in FIG.2) of the probe (e.g., 100 shown in FIG. 2) to tissue. Products of theexothermic reaction may be directed away from the heat-transfer portion(e.g., 12 shown in FIG. 2) via a fluid-flow path (e.g., 56 shown in FIG.2) in fluid communication with a fluid reservoir (e.g., 243 shown inFIG. 2) disposed in the handle assembly (e.g., 200 shown in FIG. 2).

FIG. 10 is a flowchart illustrating a method of delivering thermalenergy to tissue according to an embodiment of the present disclosure.In step 1010, an ablation device (e.g., 102 shown in FIG. 3) isprovided. The ablation device (e.g., 102 shown in FIG. 3) includes ahandle assembly (e.g., 300 shown in FIG. 3) and a probe (e.g., 110 shownin FIG. 3) extending from a distal end (e.g., 7 shown in FIG. 3) of thehandle assembly. The handle assembly includes a cartridge unit (e.g.,340 shown in FIG. 3) housing a first chamber (e.g., 341 shown in FIG. 3)containing a first fluid, e.g., an acid, and a second chamber (e.g., 342shown in FIG. 3) containing a second fluid, e.g., a base. The probe(e.g., 110 shown in FIG. 3) includes a mixing junction (e.g., 360 shownin FIG. 3) and first and second fluid-flow paths (e.g., 350 and 353shown in FIG. 3) in fluid communication with the mixing junction. Thefirst fluid-flow path (e.g., 350 shown in FIG. 3) is in fluidcommunication with the first chamber (e.g., 341 shown in FIG. 3), andthe second fluid-flow path (e.g., 353 shown in FIG. 3) is in fluidcommunication with the second chamber (e.g., 342 shown in FIG. 3).

In step 1020, the probe (e.g., 110 shown in FIG. 3) is positioned intissue. Ultrasound, computed tomography (CT) guidance, or other guidancemay be used to accurately guide the probe into the area of tissue to betreated.

In step 1030, one or more moveable members (e.g., 380 shown in FIG. 3)operably coupled to the cartridge unit (e.g., 340 shown in FIG. 3) aremoved to cause fluid flow of the acid and the base to the mixingjunction (e.g., 360 shown in FIG. 3) to cause an exothermic chemicalreaction.

In step 1030, thermal energy released by the exothermic chemicalreaction is delivered through at least a portion of the probe (e.g., 110shown in FIG. 3) to tissue.

The above-described tissue ablation devices and system including thesame are capable of directing thermal energy to heat, ablate and/orcoagulate tissue without the use of electromagnetic radiation. Thecapability to provide ablative thermal heat without the use ofelectromagnetic radiation may enhance device portability and locationindependence, and may help to facilitate improved patient accessibilityto hyperthermic treatments.

Although embodiments have been described in detail with reference to theaccompanying drawings for the purpose of illustration and description,it is to be understood that the inventive processes and apparatus arenot to be construed as limited thereby. It will be apparent to those ofordinary skill in the art that various modifications to the foregoingembodiments may be made without departing from the scope of thedisclosure.

What is claimed is:
 1. An ablation device, comprising: a handle assemblyhaving a controller unit disposed therein, the controller unit operablyassociated with a user interface including a user-operable switchelectrically coupled to the controller unit; and a probe operablycoupled to the handle assembly, wherein the probe includes aheat-transfer portion and at least one fluid-flow path in fluidcommunication with the heat-transfer portion, wherein the handleassembly includes at least one fluid reservoir in fluid communicationwith the at least one fluid-flow path and at least one apparatusconfigured to cause fluid flow between the at least one fluid reservoirand the heat-transfer portion, wherein the probe is configured to applythermal energy released by an exothermic chemical reaction when fluidfrom the at least one fluid reservoir is caused to flow to theheat-transfer portion.
 2. The ablation device of claim 1, wherein the atleast one apparatus configured to cause fluid flow between the at leastone fluid reservoir and the heat-transfer portion includes an actuatorunit including at least one actuator.
 3. The ablation device of claim 2,wherein the controller unit is communicatively associated with the atleast one actuator and adapted to generate an electric signal forcontrolling an operation of the at least one actuator.
 4. The ablationdevice of claim 3, wherein the at least one apparatus configured tocause fluid flow between the at least one fluid reservoir and theheat-transfer portion further includes a cartridge unit configured tohouse the at least one fluid reservoir, the cartridge unit operablycoupled to the at least one actuator.
 5. The ablation device of claim 4,wherein the probe further includes a coolant chamber disposed about atleast a proximal portion of the probe, the coolant chamber in fluidcommunication with the cartridge unit.
 6. The ablation device of claim1, further comprising a self-contained power source.
 7. The ablationdevice of claim 6, wherein the power source includes at least onebattery.
 8. The ablation device of claim 7, wherein the user interfacefurther includes an indicatory unit for providing a signal indication ofbattery condition.
 9. A system for ablating tissue, comprising: anablation device capable of utilizing an exothermic chemical reaction,the ablation device including: a handle assembly including a distal endand a cartridge unit, wherein the cartridge unit includes a firstchamber defined therein and configured to contain a first fluid, asecond chamber defined therein and configured to contain a second fluid,and a third chamber defined therein and configured to receive a productof an exothermic chemical reaction between the first and second fluids;and a probe extending distally from the distal end of the handleassembly, wherein the probe includes a mixing junction and first andsecond fluid-flow paths in fluid communication with the mixing junction,the first fluid-flow path in fluid communication with the first chamberand the second fluid-flow path in fluid communication with the secondchamber.
 10. The system of claim 9, wherein the first fluid is an acid.11. The system of claim 10, wherein the acid is selected from the groupconsisting of hydrochloric acid (HCl), hydrobromic acid (HBr),hydroiodic acid (HI), sulfuric acid (H₂SO₄), nitric acid (HNO₃), chloricacid (HClO₃) and perchloric acid (HClO₄).
 12. The system of claim 9,wherein the second fluid is a base.
 13. The system of claim 12, whereinthe base is selected from the group consisting of potassium hydroxide(KOH), barium hydroxide (Ba(OH)₂), caesium hydroxide (CsOH), sodiumhydroxide (NaOH), strontium hydroxide (Sr(OH)₂), calcium hydroxide(Ca(OH)₂), lithium hydroxide (LiOH), rubidium hydroxide (RbOH),magnesium hydroxide (Mg(OH)₂), alanine (C₅H₅NH₂), ammonia (NH₃),methylamine (CH₃NH₂) and pyridine (C₅H₅N).
 14. The system of claim 9,wherein the first fluid includes hydrochloric acid (HCl) and the secondfluid includes a metal oxide reactable with HCl to produce theexothermic chemical reaction.
 15. The system of claim 9, wherein thecartridge unit further includes a fourth chamber containing a coolantfluid.
 16. The system of claim 9, further comprising: a power sourceelectrically coupled to the ablation device.
 17. The system of claim 9,further comprising: a coolant source in fluid communication with theablation device.
 18. An ablation device, comprising: a handle assembly;and a probe operably coupled to the handle assembly and configured toapply thermal energy to tissue, the probe including a heat-transferportion in communication with at least one of a first fluid-flow pathand a second fluid-flow path, the handle assembly including a firstfluid reservoir in communication with the first fluid-flow path andcontaining a first fluid, a second fluid reservoir in communication withthe second fluid-flow path and containing a second fluid, and a thirdfluid reservoir in communication with the heat-transfer portion, thethird fluid reservoir configured to receive a product of contacting,within the heat-transfer portion, the first fluid with the second fluid.